Automatic injection device

ABSTRACT

The present invention provides an auto-injection device including a housing, a container from which a product is dispensed by advancing a piston, the container shiftably accommodated by the housing and carrying a needle, and a drive unit including a driven member, wherein the driven member is shiftably accommodated by the housing and, during an auto-injection, is adapted for inserting the needle and advancing the container to a predetermined frontal position in relation to the housing and advancing the piston within the container for dispensing of the product, wherein the driven member remains uncoupled with the piston until the container reaches its frontal position, and upon the container reaching its frontal position, the driven member detaches from the container and couples with the piston for advancing the piston within the container.

RELATED APPLICATIONS

This application claims the priority of German Patent Application No.198 22 031.6 filed May 15, 1998, which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

The invention relates to an auto-injection device. Such auto-injectiondevices are used for the administration of products, in particularmedically or cosmetically effective fluids. For administration, aninjection needle through which the product is dispensed is automaticallyinserted into a tissue by a predetermined path length after having beentriggered by a drive mechanism.

Auto-injection devices typically comprise a housing, a containershiftably or moveably accommodated by the housing from which a productto be administered is dispensed through a needle arranged at an outletof the container by advancing a piston, and a driven member of a driveunit, the driven member being shiftably accommodated by the housing.During auto-injection, the driven member advances the container inrelation to the housing in the forward direction to a predeterminedfrontal position for inserting the needle, and the driven memberadvances the piston within the container for dispensing the product.When the container has reached its frontal position during anauto-injection, the needle has been advanced by a predetermined pathlength with respect to the container. The path length may also determinethe penetration depth of the needle.

Auto-injection devices of the described design are known from U.S. Pat.Nos. 5,514,097; 159,192; and 5,643,214; as well as European Patent No. 0516 473 B1. In the known auto-injection devices, the container isadvanced together with the attached needle by a pressure which thedriven member exerts on the piston.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an auto-injection deviceensuring that a product to be administered is only dispensed upon aninjection needle having been completely advanced when being insertedinto a tissue.

In one embodiment, the present invention provides an injection devicecomprising a housing, a container shiftably accommodated by saidhousing, carrying a needle and accommodating a moveable piston, and adrive unit comprising a driven member shiftably accommodated by saidhousing wherein, during an injection, the driven member is adapted forinserting said needle and advancing said container to a predeterminedposition in relation to said housing, at which said predeterminedposition said driven member is decoupled from said container and coupledwith said piston for moving said piston within said container.

In one embodiment, an auto-injection device for administering a productin accordance with the present invention comprises at least a housing, acontainer shiftably accommodated by said housing and a driven member ofa drive unit. The product is dispensed from the container through aneedle at an outlet of the container by advancing a piston arranged inthe container. The driven member is shiftably accommodated by thehousing. During an auto-injection for inserting the needle, the drivenmember advances the container to a predetermined frontal position inrelation to the housing and advances the piston within the container fordispensing all or part of the product. The driven member is not coupledwith the piston until the frontal position of the container is reached.Upon reaching the frontal position of the container, it is decoupledfrom the container and coupled with the piston for advancing the pistonwithin the container.

Accordingly, advancement of the container for inserting the needle isnot effected by the piston, i.e., during this phase of movement there isno drive connection between the driven member and the piston. This rulesout the possibility that the product may be dispensed prematurely duringadvancement of the container by even a small forward movement of thepiston within the container, i.e., in relation to the container. Bydisengaging, i.e., decoupling, the driven member from the container andengaging it, i.e., coupling it, with the piston not earlier when thecontainer is in its frontal position, the piston will only be advancedwithin the container upon the needle being inserted into the tissue tothe required depth. The separation of the advancement of the containerand the advancement of the piston within the container at the side of adrive mechanism increases dosing accuracy, due to pressure on the pistonnot being applied during advancement of the container, thus preventingthe product from being dispensed prematurely.

The driven member may act directly on the container for advancement ofthe container.

In one embodiment, a transfer member is provided, which is driven alongby the driven member during forward advancement, thus acting on thecontainer and/or the container holder and resulting in advancement ofthe container. The transfer member may also be a container holder, butmay be designed as a part separate therefrom.

The disengageable coupling may exist between the driven member and thetransfer member. After disengaging the coupling in the frontal positionof the container, a further advancement of the driven member, i.e., foradvancement of the piston, does not result in any further advancement ofthe transfer member. The driven member now may be disengaged from thetransfer member with respect to its own forward movement. It only pushesagainst the piston and drives the piston forward in the container. Inone embodiment, the transfer member is accommodated by the housingshiftably in and against the direction of advancement of the piston.

In one embodiment, the driven member and the container are coupled toeach other by a purely positive locking. In another embodiment, thecoupling includes a non-positively locked connection between the drivenmember and the container. Hybrid locking connections may also be used.

A positively locked connection of the driven member and the transfermember may be formed by the driven member being connected to a firstcoupling means and the transfer member being connected to a secondcoupling means, with these two coupling means together forming abolt-and-lock connection which is released at that point in time atwhich the container reaches its frontal position. The first couplingmeans may be rigidly connected to the driven member and effecting anadvancement of the transfer member by pushing against a stop face of thetransfer member. In one embodiment, the first coupling means is simply acam projecting from the driven member. In the course of unlocking andthe ensuing decoupling of the driven member from the transfer member,the cam, acting like a blocking bolt, is brought into coverage with arecess ending in the stop face, with the cam no longer pushing againstthe stop face and, so-to-speak, opening the lock by falling into thelock. The driven member is released from the transfer member, thus alsoreleasing the coupling with the container, enabling the driven member tomove further forward, in relation to the transfer member. In the courseof this movement in relation to the transfer member, the driven membercomes into pushing contact against the piston, thus effecting couplingof the driven member with the piston. The blocking bolt could also beconnected to the transfer member and the lock to the driven member.

The decoupling of the driven member from the transfer member is may beeffected by rotation of one of the two members in relation to the other.This relative rotation may be effected around a rotational axis parallelto the shift direction. The relative rotation is generated compulsorilydue to advancement, in one embodiment by a coulisse guiding formedbetween the member to be rotated and the housing. Although a frictionalforce generated during the rotation may be used for selectivelyaffecting the forward speed of the driven member and the transfermember, the coupling as such, i.e., blocking and releasing, is purely apositive locking effect.

In another embodiment, a combined positive and non-positive lockingconnection is used for coupling and decoupling the driven member withand from the container and with and from the piston. In this embodiment,the coupling may be formed between the driven member and a transfermember, although coupling directly with the container would also bepossible.

The coupling may, in one embodiment, be formed by a snap coupling.During advancement of the driven member, a snapper (which also may bereferred to as a snapper or snap member) pushes against a contactpressure surface, thus advancing the container. When the container hasreached its frontal position, in which it is positioned against a stopin relation to the housing, the snap coupling is released by the driveforce continuing to be exerted to the driven member. The driven memberis then coupled to the piston and advanced further, free from thecontainer and/or free from a transfer member. A slight supporting pushupon reaching the frontal position of the container may certainly bedesirable.

One or more of the means forming the coupling may be flexible made fromproducts such as elastic. One or more snappers may be directly formed onthe driven member, which is pushing therewith against a stop face on thecontainer or the transfer member, should this be used. Such snappers mayalso be provided on the transfer member.

A third coupling means may also be used to provide the coupling. Thethird coupling may be flexible, such as a flexible elastic. The thirdcoupling means may also be a flexible washer, in particular a springwasher, clamped between two opposite faces, one of the driven member,and the other of the transfer member, and being pushed over one of thesetwo contact pressure surfaces as soon as the container has reached itsfrontal position.

The invention may also be advantageously used in such auto-injectiondevices in which the container is formed by a so-called multi-chamberampoule. With these multi-chamber ampoules, the product to beadministered is obtained only upon assembling the device by mixing thecontents of several chambers which are separate from each other. Each ofthe chambers arranged in line is closed at its rear by a pistonshiftably accommodated within the container. For mixing, a mixing memberis pushed against the rear piston and pushes, in the course of itsadvancement within the container, each of the pistons forward to themost frontal piston. During advancement, a connection is made to eachrespective adjacent frontal chamber, thus displacing the content of eachrear chamber to the respective adjacent chamber in front of it.

According to the invention, the mixing member, which may be a mixingtube, also forms the transfer member for advancement of the container.According to the invention, the mixing member has been allocated a dualfunction. From a design point of view, this may be achieved by themixing member comprising a web radially extending outwards, preferablyhaving the shape of a circumferential shoulder, for pushing against therear face of the container or, if preferred, against a rear contactpressure surface of the container holder, the container holder in itsforward movement being forced by the mixing member to take the containeralong with it. The frontal position of the container may be defined bythe container holder striking the housing.

The housing may enclose both the container and the entire drive unit andmay have the shape of a sleeve. In its most general design, however, thehousing serves as a base section only, in relation to which displacementof the container and displacement of the driven member of the drive unitis effected and must therefore not exclusively be seen as a surroundinghousing, although such an embodiment is possible.

Other features and advantages of the injection devices and methods ofthe present invention will become more fully apparent and understoodwith reference to the following description and appended drawings andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a longitudinal view of an auto-injection device in accordancewith the present invention;

FIG. 1b is a view of the coupling of the transfer member and drivenmember of the embodiment of FIG. 1a;

FIG. 2a is a longitudinal view of a second embodiment of anauto-injection device with a positive locking coupling;

FIG. 2b is a cross sectional view along line A—A of FIG. 2a;

FIG. 3 is a plane view of the transfer member of the embodiment of FIG.2a;

FIG. 4 is a view of a portion of the embodiment of FIG. 2a;

FIG. 5 is a second view of a portion of the embodiment of FIG. 2a;

FIG. 6a is a longitudinal view of an embodiment of an auto-injectiondevice of the present invention including a dual-chamber ampoule and amixing tube designed as a transfer member;

FIG. 6b is a second longitudinal view of the embodiment of FIG. 6a;

FIG. 6c is a cross sectional view along line C—C of FIG. 6a;

FIG. 6d is a cross sectional view along line D—D of FIG. 6a;

FIG. 6e is a cross sectional view along line E—E of FIG. 6a;

FIG. 6f is a cross sectional view along line F—F of FIG. 6a;

FIG. 6g is a cross sectional view along line G—G of FIG. 6a;

FIG. 6h is a cross sectional view along line H—H of FIG. 6a; and

FIG. 6i is a view of a portion of the embodiment of FIG. 6a;

DETAILED DESCRIPTION

The accompanying Figures and this description depict and describeembodiments of the automatic injection device and method of the presentinvention. With regard to means for fastening, mounting, attaching,coupling or connecting the components of the present invention to formthe device and system as a whole, unless specifically describedotherwise, such means are intended to encompass conventional fastenerssuch as machine screws, nut and bolt connectors, machine threadedconnectors, snap rings, hose clamps such as screw clamps and the like,rivets, nuts and bolts, snap fittings, toggles, pins and the like.Components may also be connected by adhesives, glues, welding,ultrasonic welding, and friction fitting or deformation, if appropriate.Unless specifically otherwise disclosed or taught, materials for makingcomponents of the present invention may be selected from appropriatematerials such as metal, metallic alloys, natural and manmade fibers,vinyls, plastics and the like, and appropriate manufacturing orproduction methods including casting, extruding, molding and machiningmay be used.

Any references to front and back, right and left, top and bottom andupper and lower are intended for convenience of description, not tolimit the present invention or its components to any one positional orspacial orientation.

FIG. 1a is a longitudinal section of an auto-injection device which isan injection pen.

The pen comprises a hollow cylindrical housing, which is a circularcylindrical shape in the embodiment of FIG. 1a, comprising a needleprotection 1 at its frontal end, followed by a frontal housing sleeve 2and an adjacent rear housing sleeve 3 including a housing cap 4,completing the rear housing sleeve 3 at the rear. The frontal housingsleeve 2 surrounds a cylindrical container B, which may be held in acontainer holder 30 coaxially centered to the central longitudinal axisof the housing. The container holder 30 is also sleeve-shaped, ending atits front in centering tongues which press against the circumferentialedge of the container B and center the same in the frontal housingsleeve 2. The container holder 30 is shiftable back and forth along thecentral longitudinal axis of the housing. During forward advancement ofthe container holder 30, the container B arranged therein is alsoshifted. Thereby, an injection needle N, arranged at an outlet of thefrontal end of the container B, is advanced and inserted into and undera patient's skin during an auto-injection.

The container B comprises a piston K, shiftable along the centrallongitudinal axis of the container B. When shifting the piston K in theforward direction, a product in the container B, in one embodiment aliquid active substance, such as insulin, is displaced through theoutlet into and through the injection needle N for dispensing theproduct. A piston rod is projecting from the rear of the piston K overthe rear edge of the container.

The container B is widened by a flange along its rear edge. Thecontainer holder 30 is also widened accordingly at its rear end andcontinued beyond the container over a distance by a widened sectionhaving the shape of a sleeve. In assembled condition, the rear widenedsection of the container B rests on the shoulder face of the containerholder 30 facing this widened section. An external jacket face of thecontainer holder 30 is surrounded by a compression spring acting as arestoring element 33 being in contact with its frontal end with ashoulder face of the frontal housing sleeve 2, from where it projectsalmost to a counterface 31, formed by the widened section of thecontainer holder 30, said counterface facing said shoulder face of thefrontal housing sleeve 2. During advancement of the container holder 30and therefore of the container B, the compression spring 33 iscompressed between the two faces facing each other, thus cushioning theforward movement of the needle N during insertion. During advancement,the face 31 strikes against a shoulder face formed in the area of astepped widened section of the frontal housing sleeve 2. The stop of theshoulder face 31 of the container holder 30 defines a frontal positionof the container B and therefore the length by which the needle Nprojects over the frontal edge of the housing in frontal position of thecontainer B, simultaneously also specifying the insertion depth of theneedle N if the pen is correctly placed on the skin.

A drive unit for advancement of the container B and the piston K withinthe container B is formed by a drive element 5 designed as a compressionspring, and a driven member 10. Drive force could also be applied by apressurized medium. The driven member 10 may be sleeve-shaped, includinga rearwardly open sleeve pot, completed by a base. The driven member 10is extended in sleeve shape at its frontal end toward the piston rodbeyond the base over a relatively short distance. The extension isformed by a plunger 11 for pushing against the piston rod and advancingthe piston K within the container B.

In the initial position of the injection pen shown in FIG. 1a, there isno direct pushing of the plunger 11 against the piston rod. A smallclearance remains between the plunger 11 and the rear face of the pistonrod. In the initial position of the pen, in which the container B is inits rear shift position, the driven member 10 is coupled to thecontainer B. The driven member 10 is directly coupled to a transfermember 20 which in turn directly affects the container B.

The transfer member 20 could alternatively directly affect the containerholder 30. In this case a drive dog would have to be provided betweenthe container holder 30 and the container B. In principle, the drivenmember 10 could push directly on a container B or a container holder 30in order to advance the needle N.

As shown in FIG. 1b, the transfer member 20 is formed by a sleeve body,with a circumferential shoulder 22 formed in its rear section byreducing the cross-sectional area, the shoulder 22 acting as a frontalcontact pressure surface for an elastic spring washer 21. The elasticspring washer 21 is held blocked against shifting in relation to thedriven member 10 in a groove surrounding the external jacket surface ofthe driven member 10 within the area of the plunger 11. The washer 21may be designed as a fully closed, soft elastic washer, but may also bemade of a hard material, such as plastic or metal, open at one point, toallow the ends of the washer 21 facing each other to be moved towardeach other over a distance, thus allowing the diameter of the washer 21to be reduced. The flexible washer 21, the shoulder 22 and the wall 12of the groove facing the shoulder 22 form a releasable positive andnon-positive locking coupling between the driven member 10 and thetransfer member 20. The washer 21, as compression and coupling means,could also be designed as a bead on the driven member 10 or the transfermember 20, which would end in such an embodiment at the front inbendable tongues.

The driven member 10 is held against the pressure of the drive element 5in its initial position shown in FIG. 1a by a blocking and releasesleeve 6 by means of a release tab 7 formed on the blocking and releasesleeve 6. The connection is released by pushing the release tab 7inward.

For injection of the product, the pen is positioned on the skin with thefrontal edge of the needle protection 1 under light pressure afterremoving the needle protection. Then the release tab 7 is pressed, thusreleasing the connection between the release sleeve 6 and the housing.The driven member 10 is then advanced in a forward direction within thehousing under the pressure of the drive element 5. The couplingtransfers the forwardly shifting force of the driven member 10 from thegroove wall 12 to the washer 21 and from there to the shoulder 22 andtherefore to the transfer member 20. The transfer member 20 pushes withits frontal face against the container B and the container holder 30which are advanced in the housing under the contact pressure of thetransfer member 20, initially without resistance apart from wallfrictional forces. The needle N, pointing accurately in the forwarddirection, is pushed forward beyond the frontal edge of the needleprotection 1 and penetrates into the tissue. The advancement of thecontainer B and therefore the penetration depth of the needle N arelimited by pushing the shoulder face 31 of the container holder 30against the counterface on the housing. The container B is now in itsfrontal position.

During the advancement of the container holder 30 and the container B,there exists the engagement, i.e., the drive coupling, of the drivenmember 10 and the transfer member 20. The coupling is designed to bereleased upon the container B reaching its frontal position (orforwardmost extent of travel in the direction of the needle, whichfrontal or forwardmost position may be adjustable or selectable in someembodiments).

This is achieved by the dimensioning of the flexible washer 21 and theshaping of the shoulder 22, serving as a stop for the washer 21. Theshoulder 22 extends in the forward direction obliquely or in a curvefrom the wider rear section to the narrower frontal section of thetransfer member 20.

The flexible washer 21 is round in cross section. In principle, theshape of the cross section of the washer 21 and the shape of theshoulder 22 need to be adjusted to each other only in such a manner thatthe flexible washer 21 does not shift over the shoulder 22 prior to thecontainer having reached its frontal position. For this the coupling hasto transfer at least the reaction force existing during advancement ofthe container B and the force required for inserting the needle N, andmust not block after the container has reached its frontal position butbeing securely released. The adjustment of the coupling is at itsoptimum when released, and is subject to minimum jerking.

When the coupling, formed by the coupling means 12, 20, 21 and 22, hasbeen released or even during release, the driven member 10, advancingfurther subject to the pushing of the drive element 5, comes intopushing contact with the piston rod, thus being coupled to the piston K,which advances within the container B under the contact pressure appliedby the driven member 10, thus displacing product and dispensing itthrough the needle N.

In order to compensate for a decrease in power of the drive element 5,which accompanies the advancement of the driven member 10, the internaljacket face of the transfer member 20 may be conically widened. Thewasher 21 would be subject to frictional forces which decrease with theadvancement of the driven member 10 due to such widening. This featureof controlled dampening of the drive force would benefit from theelasticity of the washer 21 or some other contact pressure means havingthe same effect, i.e., such as a damper for compensation.

As an alternative to this compensation based on the control of slidingfrictional forces, a decrease in drive force may also be compensated forpneumatically. In the case of pneumatic compensation, the spacesurrounded by the jacket faces of the driven member 10 and the transfermember 20 may be sealed hermetically as far as possible. The guide ring18 inserted at the rear end of the transfer member 20 may be designed asa sealing washer to the driven member 10, which itself would form apiston. In addition, the slideways formed between the internal jacket ofthe transfer member 20 and the opposing face of the plunger 11 could bedesigned as sealing faces. This would form a cavity between the externaljacket face of the driven member 10 and the internal jacket face of thetransfer member 20, with the cavity increasing during advancement of thedriven member 10.

Only a calibrated passage would have to be provided in the guide ring 18designed as a seal, through which a medium, such as air, could flow intothe otherwise sealed cavity. The depression generated by the advancementof the driven member in this cavity would be subject to delayedcompensation only, such that the forward speed of the driven member 10may remain constant over the entire stroke of the piston K.

The spring 33 may have a cushioning effect and may therefore delay theforward movement of the container holder 30 together with the containerB, although the container holder 30 and the container B are movedinitially over part of the distance which is not impeded by the spring33, due to the shoulder 31 of the container holder 30 only pushingagainst the spring 33 after completing the movement. Forward movementover the remaining distance to the frontal container position may thenbe decelerated by the lower returning force of the spring 33 versus theforce exerted by the drive element 5. As desired, a fast penetration ofthe needle followed by decelerating its forward speed in the lowertissue layers is achieved. Stop tabs 2 a, provided on the frontalhousing sleeve 2 retain the container holder 30 in its rear position.Under the pressure of the drive element 5 and therefore the containerholder 30 upon being released, the stop tabs 2 a, however, will yield.By means of a tensioning handle 7′ projecting into the housing, theblocking and release sleeve 6 and the driven member 10, which areshiftably accommodated in the housing in the rear position, are returnedto their rear position and retensioned. The driven member 10 and thesleeve 6 are suitably connected to each other. In the rear position anew container B can now be inserted.

FIG. 2a is a longitudinal section and FIG. 2b is a cross section alongline A—A FIG. 2a of a second embodiment of an auto-injection device,again constituting a pen. In this pen, the drive connection between thedriven member 10 and the container B and the driven member 10 and thepiston K is purely effected by positive locking and releasing. As anadditional difference, this embodiment may contain a needle safetysleeve covering the needle N after retraction from the tissue, thusreducing the risk of injury during subsequent handling.

The housing is also formed by a frontal housing sleeve 2 and a rearhousing sleeve 3. In this embodiment, the needle protection 1 is anintegral part of the frontal housing sleeve 2. In the hollow cylindricalhousing, again, a container holder 30 in which a container B filled witha product to be administered is kept in a centered position, supportedsmilingly in a shiftably position back and forth along the longitudinalaxis of the housing. During advancement for inserting the needle N, thefrontal stop face 31 of the container holder 30 is advanced against astop formed by the housing, thus defining the frontal position of thecontainer B and the insertion depth of the needle N. After injection,the two housing sleeves 2 and 3 are unscrewed, thus releasing thecontainer B and the container holder 30 from the transfer member 20 andreturning the container holder 30, subject to the pressure applied bythe restoring element 33, which may be designed as a restoring spring,with a rear stop face 31 against a stop face formed by the housing intoits rear position, i.e. the initial position. In this rear position anew container B can be inserted. After screwing the two housing sleeves2 and 3 together, the pen of FIG. 2 is ready for the next injection.

As described for the embodiment of FIG. 1, the driven member 10 of thepen of FIG. 2 acts on the container via a transfer member 20. In thesame way, the transfer member 20 could act on the container holder 30,in turn driving it along with the container B. The advancement of thepiston K within the container B is due to direct contact pressure of theplunger 11 of the driven member 10 being applied to the piston rodprojecting rearwardly out of the container B, the piston rod beingattached to the piston K or moulded as an integral part of the piston K,starting from its rear.

FIG. 3 is a drawing of the driven member 10, the transfer member 20 anda guide means 40 according to their position in FIG. 2a. With referenceto coupling and releasing the driven member 10 to and from the transfermember 20, reference is also made to the drawing of FIG. 3.

The driven member 10 is formed by a fully cylindrical base body,comprising a plunger 11 with a widened cross section. Again, the driveelement 5 is formed as a compression spring, surrounding a cylindershaft section of the driven member 10. In the initial position of thepen, the drive element 5 is clamped between the thickened plunger 11 andthe ribs 9 projecting from the rear housing sleeve 3 radially towardsthe inside and cylindrical shaft section. The driven member 10 is heldin initial position by means of snappers 15.

Several snappers 15 may project from the cylinder shaft section as anextension of the cylinder shaft section of the driven member 10 and maygrip behind the ribs 9 extending radially inwards.

A rib or cam 13 extends from the external jacket face of the plunger 11.With its cam 13 the driven member 10 is stopped against a rear face 23of the transfer member 20. The transfer member 20 is formed by a simplyhollow cylindrical sleeve, preferably a circular cylindrical sleeve,from the external jacket face of which in a rear section a cam 25extends radially outward. A release groove 24, as shown in FIG. 3, isrelieved in the internal jacket face of the transfer member 20, with therelease groove 24 extending in the longitudinal direction of thetransfer member 20 and ending in the rear face 23. The minimum size ofsaid groove 24 may be adapted such that the cam 13 of the driven member10 can engage in the groove 24.

The transfer member 20 is shiftably arranged in a longitudinal directionand rotatable about its longitudinal axis in a hollow cylindrical,perhaps circular cylindrical sleeve. This sleeve forms a guide means 40,or simply a guide, for the transfer member 20 such that a shiftingmovement of the transfer member 20 in relation to the guide means 40 isconverted into rotation of the transfer member 20 around itslongitudinal axis in relation to the guide means 40, i.e., the shiftingmovement being superimposed by rotation. In this embodiment, the guidemeans 40 is designed as a separate sleeve, accommodated in the housingand secured against rotation and shifting. In principle, it could forman integral part of the housing, in this embodiment with the rearhousing sleeve 3, which may, however, result in increased productionexpenditure.

The relative rotation of the transfer member 20 in relation to the guidemeans 40 and the driven member 10 guided straight and secured againstrotation in the housing, is effected by means of a coulisse guidingbeing formed between the transfer member 20 and the guide means 40.

The design of the coulisse guiding, as shown in FIG. 3, provides a guidegroove 41 for the cam 25, the guide groove 41 being relieved in theinternal jacket face of the guide means 40 opposite to the cam 25 of thetransfer member 20. The guide groove 41 comprises a rear straight groovesection 42 and a chamfered second groove section 43 extending in acurve, i.e., the second groove section 43 comprises a component pointingtransversally to the forward direction of the transfer member 20, andthe second groove section 43 may have an end which is simply chamfered.In the initial position, the cam 25 is positioned in the groove section42.

Referring again to FIG. 2a, a release mechanism may comprise an externalsleeve 4, a release button 7 and a restoring spring 8. The externalsleeve 4 may surround the rear section of the rear housing sleeve 3, theexternal sleeve 4 being shiftable back and forth on the external jacketface of the rear housing sleeve 3 along its longitudinal axis. Therelease button 7 is inserted into a central opening of the rear face ofthe external sleeve 4, projecting through this opening with an internalsleeve extending close to the snappers 15 of the driven member 10.

The pen of FIG. 2a may be pressed against the skin for injection suchthat a needle safety sleeve 50 being shiftable within the frontalsection of the frontal housing sleeve 2 in the longitudinal direction isshifted against the pressure of a restoring unit 51, into the frontalhousing sleeve 2 below the needle protection 1. In this condition, theneedle N is still set behind the frontal edge, formed by the frontalends of the needle protection 1 and the needle safety sleeve 50.

Inserting the needle N and dispensing the product are effected bypressing the release button 7 in the longitudinal direction of the pentoward the driven member 10 and its snappers 15. The internal sleeve ofthe release button 7 may then be pushed over the rear ends of thesnappers 15 which in turn are bent elastically and radially inwardtoward each other, whereby the engaging connection is released from theribs 9 of the housing.

The pressure applied by the drive element 5 is transferred by thereleased driven member 10, the cam 13 of which is pressed against therear face 23 of the transfer member 20, to the transfer member 20, whichin turn presses its frontal face against a rear flange face of thecontainer B. The container B presses against the container holder 30 bythe frontal face of the same flange, which in turn presses against ablocking sleeve 60, which cannot be shifted in relation to the housing,by means of the restoring unit 33. The pressure force of the restoringelement 33, however, is low in comparison with that of the drive element5, whereby the driven member 10, the transfer member 20, and thecontainer holder 30 together with the container B are advanced along thelongitudinal axis of the housing within the housing under the pressureof the drive element 5.

During this advancement the cam 25 of the transfer member 20 slides inits guide groove 41. As soon as the cam 25 enters the second groovesection 43 during advancement, the transfer member 20 is forced, due tothe transversal component of the second groove section 43, into rotationaround its longitudinal axis. The course of the guide groove 41 has beenselected such that the release groove 24 which is relieved in thetransfer member 20 and ends in the face 23, comes into an overlappingcoverage with the cam 13 due to the forced relative rotation in relationto the housing and the driven member 10.

As soon as the release groove 24 overlaps the cam 13, the driven member10 is decoupled from the transfer member 20. The course of the guidegroove 41 has been selected such that the overlapping coverage isestablished as soon as the frontal stop face 31 of the container holder30 pushes against the stop of the housing, the container B being at thesame time in the frontal position. The decoupling, i.e., the release,allows the driven member 10 to advance further in relation to thetransfer member 20 under the pressure of the drive element 5, pushingagainst the piston rod to displace the piston K within the container Bunder the direct contact pressure of the driven member 10 until theproduct has been dispensed.

Inserting the needle N is set as desired by the course of the guidegroove 41. Initially, the needle N is inserted very rapidly since theguide groove 41 extends straight in the forward direction during a firstpart of the forward movement of the transfer member 20, thus not posingany resistance against the advancement of the transfer member 20.Penetration speed is decelerated as the needle penetrates, due to theguide groove 41 now extending also transversely in the forwarddirection, spirally in the embodiment, whereby the transfer member 20within the guide section 43 therefore is exposed to a frictional forceduring advance, said frictional force being dependent on the slope ofthe guide section 43. In addition, the speed at which the needle N isinserted is reduced by the increasing restoring force of the restoringelement 33.

FIGS. 4 and 5, together with FIG. 2 show the mode of operation of theneedle safety unit, preventing the needle N from freely projecting fromthe housing after retracting it from the tissue and possibly beingbroken or causing injuries due to careless handling. The majorcharacteristic of the needle safety sleeve is blocking of the needlesafety sleeve 50 in relation to the housing after retraction of theneedle N, thus preventing it from being pushed into the housing. Anarrangement where the needle safety sleeve in pushed over the housingexternally could also be imagined.

FIG. 4 shows the frontal section of the pen of FIG. 2 in the frontalposition of the container B. The needle safety sleeve 50 has been pushedto its rear shift position in relation to the housing sleeve 2 againstthe pressure of the restoring element 51. The needle N projects over thehousing and the needle safety sleeve 50 by the desired length.

The needle safety sleeve 50 comprises a rear stop face and a frontalstop face, limiting the shifting path of the needle safety sleeve 50 inrelation to the frontal housing sleeve 2 in and against the forwarddirection. When the needle safety sleeve 50 is moved in eitherdirection, it passes over the blocking sleeve 60, comprising a hook 62at its frontal end, projecting obliquely or curved outward. In aninternal jacket section that slides over the hook 62, the needle safetysleeve 50 is of a slightly widened diameter, corresponding approximatelyto the length of its maximum shifting path. A transitional section 52between this widened internal frontal cross section and the subsequentinternal cross section is chamfered, thus allowing the needle safetysleeve 50 to slide over the hook 62, subject to the pressure of therestoring element 51, beyond the end of the transitional section 52. Ina central section behind the transitional section 52, the needle safetysleeve 50 is provided with longitudinal slots 53, the frontal faces 54of which, as best seen in FIG. 5, form the stop faces for one hook 62each.

The blocking sleeve 60 ends in a number of elastic and flexible tongues61, evenly distributed over the circumference of the sleeve, to the freefrontal ends of which the hooks 62 are moulded. The container holder 30also ends in tongues 34 towards its free frontal end. During advancementof the container holder 30, its tongues 34 are positioned below thetongues 61 of the blocking sleeve 60. Each of the tongues 61 istherefore supported radially inward and can no longer be bent in thefrontal position of the container. The tongues 61 are not only supportedby the tongues 34, but in addition pushed radially outwards. Incomparison with the tongues 61, the tongues 34 may be rigid.

After retraction of the needle N, the needle safety sleeve 50 is pushedforward again by the restoring element 51, pushing over said hook 62 dueto the chamfer of the surface 52 and/or the appropriate chamfer of thehook 62, the end of which may be elastic and flexible. However, as soonas the needle safety sleeve 50 has been advanced so that its stop face54 is positioned in front of the hook 62 when seen in the forwarddirection, it is blocked against shifting backward by the hook 62,stopping against the stop face 54. The hook 62 and the needle safetysleeve 50 are in contact with stop faces which are directed verticallyto the shift direction. After injection, the needle N is protected bythe needle safety sleeve 50, as shown in FIG. 5 in the safety position.

The container holder 30 may therefore be simultaneously used as ashiftable support for the elastic blocking means 62 and according to theinvention fulfils a double function, i.e., holding the container andblocking the needle safety sleeve 50. The needle safety sleeve 50 doesnot require the design of the auto-injection device according to theinvention, although this could be combined with the same. It may also beapplied advantageously in generic auto-injection devices or evenunchanged in injection devices in which insertion of the needle N byadvancement of the container B in relation to the housing is effectedmanually.

FIGS. 6a-6 i comprise a longitudinal section and views a plan view of anauto-injection pen, in which the driven member 10 is coupled to thecontainer B and the piston K, subject to positive and non-positivelocking. The coupling may in its effect be compared with that of the penof FIG. 1. In the following description, reference is also made to thecross sections (FIGS. 6c-6 h) of the plan view (FIGS. 6a and 6 b) andFIG. 6i.

The container B of the pen of FIGS. 6a-6 i may be a so-calleddual-chamber ampoule in which two product components contained in twoin-line chambers are separated, in delivery condition of the containerB, by a frontal piston K1, are initially mixed with each other byadvancement of a rear piston K2 against the frontal piston K1. Thefrontal chamber in the delivery configuration generally contains apowdered active substance, whereas a carrier fluid is stored in thechamber formed between the two pistons K1 and K2.

In the condition shown in FIG. 6b, the two components have beencompletely mixed by advancement of the rear piston K2 against thefrontal piston K1, in the frontal chamber located between the piston K1and the outlet of the container B. Again, the housing comprises afrontal and rear housing sleeve 2 and 3, firmly attached to each other,for instance, by a screw or a plug-Page type connection. A cap 4 isplugged into the rear housing sleeve 3. The frontal housing sleeve 1 isextended toward the front by a needle protection 1 and a needle safetysleeve 50′ which is pushed back for inserting the needle N against arestoring force, returning to the advanced position after injection.

The container B is pushed into a container holder 30 up to the stop andkept in the entered position. The container holder 30 is shiftablyarranged in the forward direction within the housing against thepressure of the restoring element 33.

Advancement of the rear piston K2 is effected upon assembling thefrontal housing sleeve 2 to the rear housing sleeve 3. For this purpose,a mixing member 20, designed as a sleeve, is accommodated in the rearhousing sleeve 3, secured against rotation. The mixing member 20comprises a frontal sleeve section of an external diameter smaller thanthe internal diameter of the container B and a rear sleeve sectionwidened in relation to the frontal sleeve section. The transitionbetween these two sleeve sections is designed as a shoulder 28, radiallyprojecting from the frontal sleeve section. The shoulder 28 extends allround. However, it may also be formed by one or more radially projectingwebs. The rear face of the mixing member 20 contacts the webs 9projecting radially inward from the rear housing sleeve 3, which websmay be designed as a circumferential wall. When assembling the device,i.e., upon screwing on the two housing sleeves 2 and 3, the mixingmember 20, secured against shifting in this way in the rear housingsleeve 3, is introduced into the container B, which is open at the rear,and is pushed forward in the same, whereby it pushes the rear piston K2forward toward the frontal piston K1 until the rear piston K2 hasreached the position shown in FIG. 1a. In this position of the pistonsK1 and K2, screwing the housing sleeves 2 and 3 together has also beencompleted.

The drive unit is arranged in the rear housing sleeve 3, the drive unitcomprising the drive element 5, which may be designed as a compressionspring, and the rod-shaped driven member 10, guided straight in thehousing. The drive element 5 is clamped between the webs 9 and acircumferential shoulder face of the driven member 10, said shoulderface being provided in the forward direction of and facing to the web 9.

The driven member 10 is arranged rotatably around a central longitudinalaxis of the housing, coinciding with its own central longitudinal axis,allowing rotation in either direction between two rotational positions.A dosing sleeve D, as shown in FIG. 6b, which extends the housing, isprovided for rotating the driven member 10. In its rear section,projecting into the dosing sleeve D, the driven member 10 comprisesguide grooves extending in the forward direction, into which a guidesleeve 6 a and an indicator sleeve 8 engage. The guide sleeve 6 aprojects into the cap 4 and is not shiftable but is rotatable inrelation to the cap 4. The indicator sleeve 8 is arranged in the housingrotatably but not shiftable in relation to the housing. The guide sleeve6 a may be connected to the dosing sleeve D securely against rotation,as best seen in section H—H (FIG. 6h). The guide sleeve 6 a acts totransfer rotation of the dosing sleeve D to the driven member 10. Theindicator sleeve 8, connected to the driven member 10 securedly againstrotation, is used for indication of the rotational position of thedriven member 10 and therefore indication of the set dose. For thispurpose, markings are provided on its external circumference, in theembodiment two markings, i.e., one for each of the two final rotationalpositions of the driven member 10. These markings can be read through anopening in the housing. Both the indicator sleeve 8 and the guide sleeve6 a are used together with the mixing member 20 as a straight guide forthe driven member 10.

In its rear initial position as shown, the driven member 10 is retainedby a blocking and release mechanism. The blocking and release mechanismcomprises a release means 7 a, designed in one embodiment as a releasebutton, acting transversally to the shift direction of the driven member10 on a blocking means 7 b. The construction and mode of operation ofthe blocking and release mechanism is best seen in the jointlongitudinal section and cross section F—F (FIG. 6f).

The blocking means 7 b may be formed by a sleeve body having athrough-opening through which the driven member 10 projects. Forstraight guidance transversally to the forward and longitudinaldirection of the driven member 10, the blocking means 7 b is guidedbetween two straight webs of the housing. Accordingly, the sleeve bodyof the blocking means 7 b, facing each of the two webs of the housing,comprises straight outer faces. The through-opening of the blockingmeans 7 b is larger than the external diameter of the driven member 10projecting through it. The blocking means 7 b is shifted transversallyto the forward direction of the driven member 10 against the pressure ofa restoring element 7 c, which may be designed as a compression spring,by pushing the release means 7 a. In the blocked position, the drivenmember 10 contacts a rear face of the blocking means 7 b by a shoulder29, formed by a thickened section. Transversal displacement of theblocking means 7 b releases this stop. The driven member 10 is releasedfrom the blocking means 7 b, thus allowing advancement in thelongitudinal direction subject to the pressure of the drive element 5.

A safety unit ensures that the release means 7 a can only be operated,thus releasing the driven member 10, upon a container B having beenplaced into the housing. The safety unit comprises a release andblocking mechanism 70 and a compression spring 19. The release andblocking mechanism 70 comprises a central sleeve section from which twowebs 70 a extend forward in the longitudinal direction (section E—E,FIG. 6e). The two webs 70 a are projecting through two suitably formedslots in the shoulder 28 of the mixing member 20, contacting the rearedge of the container B. A third web 70 b extends in the longitudinaldirection toward the rear from the central sleeve section of the releaseand blocking mechanism 70. This third web 70 b projects through therelease means 7 a, as best seen in the joint longitudinal section andthe two sections F—F and G—G (FIGS. 6f and 6 g).

At the level of the release means 7 a, i.e., in the section throughwhich the release means 7 a projects, the third web 70 b of the releaseand blocking mechanism 70 comprises a longitudinal slot. When actuatingthe release means 7 a, a rib 7 a of the release means 7 a, said rib 7 aprojecting radially inward, enters into this longitudinal slot if theslot of the release and blocking mechanism 70 being at the same level asthe internal rib 7 a of the release means 7 a. When seen in longitudinaldirection, behind the slotted section, the third web 70 b is designed asa closed web, i.e., without an opening. A compression spring 19 isprovided between the web 9 of the housing and a shoulder extendinginward from the internal jacket face of the central sleeve section ofthe release and blocking mechanism 70. When a container B has beeninserted, the frontal webs 70 a of the release and blocking mechanism 70push against the rear edge of the container B, thus being retained inthe position shown in the longitudinal section of FIG. 1 in which theinternal rib 7 a of the release means 7 a can enter into the slot of therelease and blocking mechanism 70, thus displacing the blocking means 7b transversally. Should no container have been inserted, the release andblocking mechanism 70 is pushed forward by the compression spring 19into the annular gap, which is then free, until the central sleevesection of the release and blocking mechanism 70 contacts the shoulder28 of the mixing member 20. In this blocked position of the release andblocking mechanism 70, the rear closed section of the third web 70 b ispositioned in front of the internal rib 7 a of the release means 7 a. Inthis case, transversal shifting of the release means 7 a is notpossible. The drive unit is therefore blocked.

A drive coupling exists between the driven member 10, projecting throughthe mixing member 20, and the mixing member 20 with the effect that themixing member 20 is driven along by the driven member 10 uponadvancement of the driven member 10, i.e., being itself shifted in theforward direction in relation to the housing. The coupling is effectedby a connection in the frontal section of the mixing member 20, theconnection residing in positive and non-positive locking, similar to thecoupling of the embodiment of FIG. 1. The mixing member 20 has beenallocated a dual function, including that of a transfer member and istherefore designated the mixing and transfer member 20 in the following.

As a variation from the coupling of the embodiment of FIG. 1, theflexible and elastic washer 21 may be accommodated in a groove formed onthe internal jacket of the mixing and transfer member 20, and the drivenmember 10 therefore only comprises a contact pressure surface 17 for thewasher 21, said contact pressure surface 17 effecting the driving alongof the mixing and transfer member 20. The contact pressure surface 17forms a first coupling means, with a contact pressure surface 27 formedby the groove of the mixing and transfer member 20 forming a second andthe washer 21 a third coupling means.

Within a section arranged in the container B, the mixing and transfermember 20 and the driven member 10 may form a dosing unit. For thispurpose, the mixing and transfer member 20 is provided with a recess inan internal jacket section being rearward of the first coupling means17. This recess comprises two grooves 25 and 26, extending in forwarddirection, arranged parallel to each other at an offset angle. Thegrooves 25 and 26 extend in forward direction with different lengths.The shorter groove 25 is formed as a dead groove in the jacket face andthe longer groove 26 is limited in the forward direction by the rear webof the accommodation for the third coupling means 21. In relation toforward direction, the rear ends of the grooves 25 and 26 are ending atthe same height in a widened section of the recess, as best seen in thelongitudinal section of FIG. 6b, in combination with sections C—C, D—Dand E—E (FIGS. 6c, 6 d, and 6 e). The widening of the recess ranges tothe rear face of the frontal sleeve section of the mixing and transfermember 20. The opposing side walls of the widened section ending thereare extended in the forward direction by one each of the two grooves 25and 26.

The driven member 10 is provided with a radially projecting cam 16. Inthe initial position of the injection device, the cam 16 engages in thewidened section of the recess in the mixing and transfer member 20. Therecess, comprising the two grooves 25 and 26, is a first dosing means,and the cam 16 forms a second dosing means of the dosing unit.

In a first dosing position, the cam 16 is located flush with the groove25 on the first side wall of the widened section, the side wallextending in the forward direction, and in the second dosing positionthe cam 16 is located flush with the groove 26 on the second side wallof the widened section of the recess, said second side wall extending inthe forward direction. In the initial position of the injection device,the driven member 10 is rotatable around its longitudinal axis in eitherdirection between these two dosing positions. The two side walls of thewidened section of the recess define the two rotational and dosingpositions of the driven member 10, and the lengths of the two narrowgrooves 25 and 26 define the volume of the active substance solutionbeing dispensable during one injection.

The widened section of the recess in the mixing and transfer member 20could also be extended to the end of the short groove 25 in the forwarddirection, thus providing a simple stepped recess in the forwarddirection.

For auto-injection, the auto-injection device is placed with its needlesafety sleeve 50′ on the surface of the tissue, in particular the humanskin, the needle safety sleeve 50′ being retractable in relation to thefrontal housing, i.e, the frontal needle protection 1. The needle safetysleeve 50′ is pushed back to its most rear position in relation to thehousing by pressure being applied against the surface of the tissue. Theinjection needle N, firmly attached to the outlet of the container Bpointing in the forward direction, is initially covered beyond its fronttip by the needle protection 1 and the needle safety sleeve 50′ coveringthe same, thus not touching the tissue surface.

After having positioned the driven member 10 into the requiredrotational and dosing position by means of the metering sleeve D, theuser pushes the release means 7 a, which may be a tab, inward in theradial direction for actuating, i.e., inserting the needle anddispensing the active substance solution. When pushing the release means7 a inwards, the blocking means 7 b, which may be a stop, is pushed awayfrom underneath the stop shoulder 29, thus releasing the driven member10. The driven member 10 is shifted forward in relation to the housingsubject to the pressure of the drive element 5. By means of the couplingthe mixing and transfer member 20 is also shifted forward. The positiveand non-positive locking between the driven member 10 and the mixing andtransfer member 20 is sufficiently strong for the mixing and transfermember 20 to be driven along, which in turn, by applying pressure by itsshoulder 28 against the container holder 30 and the container B,advances these in relation to the housing and against the restoringforce of the restoring element 33 up to a frontal position, defined by astop 31 a formed on the housing.

In the frontal position of the container holder 30 and the container B,the coupling releases the drive connection between the driven member 10and the mixing and transfer member 20. Subject to continued pressure ofthe drive element 5 and due to the fixing of the mixing and transfermember 20, the flexible washer 21 is compressed and pushed over thechamfered shoulder 17. The driven member 10 now advances further, alsoin relation to the mixing and transfer member 20, simultaneously pushingthe two pistons K1 and K2 forward in the container toward the containeroutlet. The active substance solution is dispensed through the needle N,inserted into the tissue in the frontal position of the container.

In the first dosing position, the advance movement of the driven member10 is limited by the frontal end of the groove 25. In the first dosingposition, dispensing ends upon the cam 16 touching that wall of thegroove 25 which extends in circumferential direction.

After retraction of the needle N, the injection device is prepared for asecond injection, with only the driven member 10 initially beingretracted against forward direction in relation to the mixing andtransfer member 20. The driven member 10 is provided with a plunger 11at its frontal end, having the shape of a flange-type widened section.When dispensing the active substance solution, the driven member 10pushes with its plunger 11 against the rear piston K2 and uponretracting, the rear circumferential shoulder face of the plunger 11,pushes against the web projecting from the internal jacket face of themixing and transfer member 20, forming the front wall of the grooveaccommodating the third coupling means 21. When retracted further, thedriven member 10 takes along with it the mixing and transfer member 20,i.e. up to its rear position, as shown in FIG. 1. The container holder30 and the container B located therein, follow the movement of themixing and transfer member 20 subject to the pressure of the restoringelement 33. The restoring force of the restoring element 33 may be lowas compared to the drive force of the drive element 5, therefore notinterfering upon pushing the container B forward for inserting theneedle N.

For the next injection, the driven member 10 is rotated into its seconddosing position in which the cam 16 is positioned flush with the groove26. In this position, the driven member 10 can be advanced in relationto the mixing and transfer member 20 so that the residual activesubstance solution in the container is dispensed upon the drive unitbeing actuated, i.e., by actuating the release means 7. Forward movementis limited by a circumferential web forming the rear wall of theaccommodating groove for the third coupling means 21.

In the foregoing description, embodiments of the invention have beenpresented for the purpose of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formdisclosed. Modifications or variations are possible in light of theabove teachings, and the described embodiments were chosen and describedto provide an illustration of the principals of the invention and itspractical application, and to enable one of ordinary skill in the art toutilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the invention asdetermined by the appended claims when interpreted in accordance withthe breadth they are fairly, legally, and equitably entitled.

What is claimed is:
 1. An auto-injection device for administering aproduct, comprising: a) a housing; b) a container having an outlet andcarrying a needle at said outlet, the container being shiftablyaccommodated by the housing; and c) a driven member of a drive unitoperably coupled to the housing, the driven member being shiftablyaccommadated by the housing wherein, during an auto-injection, thedriven member advances the container to a predetermined frontal positionin relation to the housing, and advances a piston within the containerfor dispensing of the product, wherein the driven member remainsuncoupled with the piston, and coupled with the container until thecontainer reaches the predetermined frontal position, and upon thecontainer reaching the predetermined frontal position, the driven memberbecomes decoupled from the container and becomes coupled with the pistonfor advancement of the piston within the container.
 2. The device ofclaim 1, further comprising: a transfer member which is driven by thedriven member, the transfer member being adapted to push the containerin a forward direction when advancing; and a coupling which affects thedriving motion between the driven member and the transfer member,wherein when the container reaches its predetermined frontal position,and the driven member advances further, the driven member advances thepiston while pushing against it within the container.
 3. The device ofclaim 2, wherein the coupling between the driven member and the transfermember comprises a first coupling means connected to the driven memberand a second coupling means connected to the transfer member, the secondcoupling means being in engagement with the first coupling means, thuscausing the driving motion of the transfer member, the engagement beingreleased by a relative rotation caused by a joint advance movementbetween the driven member and the transfer member around a rotationalaxis pointing in a forward direction.
 4. The device of claim 3, whereinthe joint advance movement is converted into the relative rotation by acoulisse guiding formed between the driven member and the housing, andwherein the transfer member and the coulisse guiding secure againstrotation and displacement.
 5. The device of claim 3, wherein the jointadvance movement is converted into the relative rotation by a coulisseguiding formed between the transfer member and the housing, and whereinthe driven member and the coulisse guiding secure against rotation anddisplacement.
 6. The device of claim 1, wherein the coupling between thedriven member and the container comprises a positive locking connection.7. The device of claim 1, wherein the coupling between the driven memberand the container comprises a non-positive locking connection of thedriven member and a transfer member.
 8. The device of claim 7, whereinthe coupling between the driven member and the container comprises afirst coupling means connected to the driven member and a secondcoupling means connected to the transfer member, the second couplingmeans being in engagement by means of a third coupling means with thetransfer member, thus causing the transfer member to be driven forward,wherein at least one of the coupling means is flexible and yields underthe influence of a force exerted at the end of the forward movement ofthe container, thus causing disengagement.
 9. The device of claim 8,wherein said third coupling means is a flexible ring, transmitting aforward pressure of said first coupling means to said second couplingmeans and being shifted beyond said first coupling means or said secondcoupling means when a predetermined maximum force acting in the forwarddirection is exceeded.
 10. The device of claim 1, further comprising adamper between a transfer member and the driven member for compensationof a decrease of a drive force effecting the advancement of the drivenmember.
 11. The device of claim 1, wherein the container is formed by amulti-chamber ampoule having a rear piston and a frontal piston, and amixing member containing a mixing tube for advancing the rear pistontowards the frontal piston, the mixing tube being a transfer member. 12.The device of claim 11, wherein said transfer member comprises a dosingmeans, which by interacting with the drive unit allows for the selectionof a product dose which is to be administered.
 13. The device of claim1, further comprising a needle safety sleeve shiftably arranged on saidhousing and being blocked in a frontal position surrounding said needleagainst rearward shifting relative to said housing when said needle isin an advanced position.
 14. The device of claim 13, further comprisinga container holder being shiftably accommodated by said housing andbeing advanced together with said container, effecting a blocking ofsaid needle safety sleeve when said container is in its frontalposition.
 15. An injection device comprising a housing, a containershiftably accommodated by the housing, the container carrying a needleand accommodating a moveable piston, and a drive unit comprising adriven member shiftably accommodated by the housing wherein, during aninjection, the driven member is coupled to the container, and advancesthe container to a predetermined position in relation to the housing,wherein, upon reaching the predetermined position, the driven member isdecoupled from the container and coupled with the piston for moving thepiston within the container.
 16. An auto-injection device foradministering a product, comprising: a) a housing; b) a container havingan outlet and carrying a needle at said outlet, the container beingshiftably accommodated by the housing; and c) a driven member of a driveunit, the driven member being shiftably accommodated by the housingwherein, during an auto-injection, the driven member advances thecontainer to a predetermined frontal position in relation to the housingand advances a piston within the container for dispensing of theproduct, wherein d) the driven member is not coupled with the piston andis coupled with the container until the container reaches thepredetermined frontal position, and upon the container reaching thepredetermined frontal position, the driven member is decoupled from thecontainer and coupled with the piston from advancing the piston withinthe container.